【摘要】 对比研究了不同退火工艺(500、800、1100℃×2 h)对激光选区熔化(SLM)成形316L不锈钢显微组织及电化学性能的影响，并探究其腐蚀机理。结果表明：经500℃退火后316L不锈钢的微观组织与SLM成形态试样差异不大，显微硬度达到250 HV0.5;经800℃退火时，“鱼鳞状”熔池边界变得模糊，形成大量长条状不规则形貌的组织，内部胞状、柱状亚结构几乎消失，显微硬度降低到221 HV0.5;当退火温度升高到1100℃时，316L不锈钢经历了再结晶过程，晶粒尺寸明显增长，胞状、柱状亚结构完全消失，位错密度降低，试样显微硬度显著下降，为173 HV0.5。SLM成形316L不锈钢钝化膜的形成与亚结构有关，亚晶界和晶界促进钝化膜的形成，耐蚀性随退火温度升高而降低，但在1100℃退火时由于发生了再结晶，耐蚀性有所提升。更多还原

【Abstract】 Effects of different annealing processes(500, 800 and 1100 ℃ for 2 h) on microstructure and electrochemical corrosion properties of 316L stainless steel formed by laser selective melting(SLM) were investigated, and the corrosion mechanism was explored. The results show that after annealing at 500 ℃, the microstructure of the 316L stainless steel is not significantly different from the SLM formed microstructure, and the microhardness reaches 250 HV0.5. After annealing at 800 ℃, the boundary of the "fish scale" molten pool becomes blurred, forming a large number of strip irregular microstructures, the internal cellular and columnar substructure almost disappears, and the microhardness decreases to 221 HV0.5. When the annealing temperature increases to 1100 ℃, the 316L stainless steel undergoes a recrystallization process, the grain size increases obviously, the cellular and columnar substructure disappears completely, the dislocation density decreases, and the microhardness decreases significantly to 173 HV0.5. The formation of passive film of 316L stainless steel formed by SLM is related to substructure. Subgrain boundary and grain boundary promote the formation of passive film, and the corrosion resistance decreases with the increases of annealing temperature, but it is improved when the annealing temperature increases to 1100 ℃ due to the recrystallization.更多还原